Internal combustion engine ignition

ABSTRACT

Improved internal combustion engine performance can be achieved by using an ignition system employing a transformer having first and second primary windings. The transformer has a secondary winding which is connected in series with conventional spark gap means such as a distributor and a plurality of spark plugs. The initial primary winding of a transformer is connected between an oscillator and one terminal of a power supply so as to, in effect, form a part of the oscillator. The oscillator is also otherwise connected between the terminals of the power supply. The auxiliary primary winding is connected across the terminals of the power supply in series with a switch means such as conventional ignition points operated in accordance with engine speed. The two primary windings are positioned adjacent to one another so as to be inductively coupled. As a result of this structure the oscillator used continuously operates both at an amplitude and at a frequency which vary depending upon whether or not the switch means is open or closed, and, hence, in accordance with engine speed.

United States Patent [1 Gordon et :1!

L5 INTERNAL COMBUSTION ENGINE IGNITION [75] lnventors: Carroll G. Gordon, Menlo Park;

Raymond C. Graham, Santa Clara, both of Calif.

{73] Assignee: Edwin Melville Edwards. Menlo Park, Calif.

[22] Filed: Oct. 1, 1973 [2]] App], No: 402,460

Related U.S. Application Data [63] Continuation-in-part of S61, No. 297480, Nov. 13.

1 51 Aug.5, 1975 Primary Eranu'ncr-Wendell E, Burns Assistant Examiner lames W. Cranson. Jr. Attorney. Agent, or Firm-Edward D. O'Brian [5 7] ABSTRACT lmproved internal combustion engine performance can be achieved by using an ignition system employing a transformer having first and second primary windings. The transformer has a secondary winding which is connected in series with conventional spark gap means such as a distributor and a plurality of spark plugs. The initial primary winding of a transformer is connected between an oscillator and one terminal of a power supply so as to, in effect, form a part of the os cillator. The oscillator is also otherwise connected between the terminals of the power supply. The auxiliary primary winding is connected across the terminals of the power supply in series with a switch means such as conventional ignition points operated in accordance with engine speed The two primary windings are positioned adjacent to one another so as to be inductively coupled. As a result of this structure the oscillator used continuously operates both at an amplitude and at a frequency which vary depending upon whether or not the switch means is open or closed, and, hence, in accordance with engine speed,

5 Claims, 1 Drawing Figure INTERNAL COMBUSTION ENGINE IGNITION CROSS REFERENCE TO RELATED APPLICATIONS This application is a continuation in part of the Ray' inond C. Graham, et al., U.S, Patent application Ser. No. 297,480 entitled Multivibrator Circuits and Ignition Systems Using the Same" filed Nov. 13, 1972. The entire disclosure of this co-pending application Ser. No. 297,480 is incorporated herein by reference.

This application is related to the copending application Ser. No. 404,104 entitled Internal Combustion Engine Operation Using Exhaust Gas Recirculation" filed Oct. 5, 1973. The entire disclosure of this last application is incorporated herein by reference.

BACKGROUND OF THE INVENTION The invention set forth in this specification pertains to what is considered to be a new and improved internal combustion engine ignition system and to what is considered to be a new and improved manner of operating an internal combustion engine using such a systern.

Virtually everyone is familier with the fact that pres ently utilized internal combustion engine systems have various inherent limitations and drawbacks. Because these items are well known it is not considered necessary to set them forth in detail in this specification. The recognition of these factors has resulted in a great deal of research and development work aimed at improving the performance of the internal combustion engine. Much of this current work is primarily directed towards reducing polluting emissions from such engines and towards increasing the amount of power which can be obtained from such engine per unit of fuel consumed.

Certain of the work indicated in the preceding has involved the construction of internal combustion engine ignition systems of a so-called electronic" or transistorized" character. At least one of of these electronic type ignition systems has been constructed so as to utilize an oscillator type network to supply power to the primary coil of conventional type step up transformer used to in turn develop an adequate voltage to bridge across a spark gap. It is considered that the prior work along these lines has not been effective to produce a desired degree ofimprovement in internal combustion engine performance. It is also considered that this is evidenced by a lack of extremely wide utilization of electronic or transistorized ignition systems even though such systems are known and even though to a degree such systems are used.

SUMMARY OF THE INVENTION From this it will be apparent that there is an existent need for improvement in the field of internal combustion engine ignition. A broad or basic object of the present invention is to fulfill this need. Thus, the invention is intended to provide new and improved internal combustion engine ignition systems. The invention is also intended to provide a new and improved method of operating such an ignition system and an internal combustion engine.

The invention has more detailed, specific objectives than are indicated by this brief discussion. It is intended to provide ignition systems which are relatively inexpensive and which may be easily and conveniently installed and used on internal combustion engines. A fur ther objective is to provide ignition systems which are capable of relatively prolonged, effective performance with a minimum of maintenance, Another objective of the invention is to provide ignition systems as indicated which are extremeiy desirable as far as performance characteristics are concerned, particularly in the areas of reducing undesirable engine emissions and in increasing the amount of power obtained from an engine per unit of fuel consumed.

These latter factors are of course relatively complex in character. The invention set forth here is primarily intended to be utilized with an internal combustion engine operated as set forth in the copending application entitled Internal Combustion Engine Operation Using Exhaust Gas Recirculation" identified in detail in a preceding portion of this specification. In accordance with the invention set forth in this related application an in ternal combustion engine is preferably operated recir culating to the combustion chamber or chambers in such an engine a significant proportion of the exhaust gases emitted from the engine under carefully controlled conditions so that the combustible mixture used in the engine is a mixture ofa conventional fuel, recir culated exhaust gases and air.

When the invention set forth in this specification is used to cause combustion of such a mixture as set forth in this related application it is considered that quite significant reductions can be achieved in exhaust emissions of unburned hydrocarbons. carbon monoxide and objectionable nitrogen oxides. Concurrently improved power output per unit of fuel is obtained even when a much lower quality of hydrocarbon fuel is used than is normally used in an engine. However, it is also consid ered that desirable results as indicated can be achieved by using the invention separate and apart from the invention entitled Internal Combustion Engine Operation Using Exhaust Gas Recirculation" indicated in the preceding, as, for example, by utilizing the present invention with a known internal combustion engine operated in a known or conventional manner except for the use of the invention set forth in this specification.

In accordance with this invention results as indicated are achieved by utilizing in an internal combustion engine ignition system having a power supply, a trans former having primary and secondary coils, a primary circuit including an oscillator connected across the terminals of the power supply and to the transformer primary coil, a secondary circuit including spark gap means connected in series with the secondary coil, said system also having switch means for controlling the operation of the oscillator the improvement which comprises: means for opening and closing said switch means in accordance with engine speed, the transformer having a second or auxiliary primary coil which is connected in series with the switch means between the terminals of the power supply, the oscillator means being connected to one terminal of the power supply through the first mentioned primary of the transformer and in addition being connected across the power supply, the first mentioned primary and the auxiliary primary being positioned adjacent to one another so as to be inductively coupled, the oscillator means being responsive to the coupling of the first mentioned and auxiliary primary coils so as to continuously operate at both an amplitude and at a frequency which vary depending upon whether the switch means is open or closed.

BRIEF DESCRIPTION OF THE DRAWING Further details of this invention are best indicated with reference to the accompanying drawing in which:

The FIGURE is a schematic view of presently preferred internal combustion engine ignition circuit in accordance with this invention.

The invention set forth in this specification embodies certain essentially intangible concepts as are set forth or defined in the appended claims. Those skilled in the field of electronics will realize that these concepts may be utilized in circuits which differ from the precise circuits illustrated as to a number of routine design factors. Thus, it is to be understood that the circuit illustrated is not to be considered as limiting the invention.

DETAILED DESCRIPTION In the FIGURE of the drawing there is shown an internal combustion engine ignition circuit in accordance with this invention which is intended to be utilized with a conventional automotive internal combustion engine (not shown). Such an engine will include a conventional distributor l2 and a series of conventional spark plugs I4 corresponding to each of the combustion chambers or cylinders in such an engine. If the invention is to be utilized with an internal combustion engine having only one combustion chamber the distributor 12 will of course be omitted, and there will be only one of these spark plugs 14. Various equivalents of a distributor 12 as are known can, of course, be employed with the invention.

An engine in which the circuit 10 is intended to be used will also normally include a conventional set of points 16 which are adapted to be opened and closed in a conventional manner in accordance with engine speed or operation in order to cause a repetitive series of sparks at the spark plugs 14 in accordance with engine operation. Because of the function of these points 16 they may be referred to as a switch means." Various switch structures which are the equivalents of conventional automotive points may be used instead of the specific automotive points 16 indicated. In theory it is possible to use the distributor 12 as the points 16, omitting these points 16. From a practical standpoint this is not considered desirable.

The circuit 10 employs a transformer 18 which differs from a conventional transformer by including concentric first and second primary coils 20 and 22, respectively, which are inductively coupled to one another. For convenience of designation the coil 22 may be referred to as an auxiliary primary winding or coil although in accordance with this invention it is not of an auxiliary character as it is used. The transformer 18 also includes a secondary winding 24 which is connected in series with the distributor l2 and any one of the spark plugs 14 through which current is directed to this distributor 12 by a wire 26. This wire 26 is also preferably electrically connected to a laminated core 28 which is preferably used in the transformer 18.

In the circuit 10 the first mentioned transformer coil 20 is connected to one terminal 30 of a conventional power supply (not shown) such as a battery used in connection with an internal combustion engine by a wire 32 leading through a conventional ignition or similar switch 34. Although it is not considered preferable the wire 32 can be directly connected to the terminal 30 so that the switch 34 is not in the connection between the power supply and the transformer coil 20. In this case the wire 36 would be connected to the terminal 30 through the switch 34. A branch wire 36 off of the wire 32 contains two conventional current control resistors 38 and 40, respectively, and it leads to one extremity of an oscillator 42 employed with this inven tion. The extremity of the primary coil 20 remote from the wire 32 is also connected to this oscillator 42 by means of another wire 44. A further wire 46 from the oscillator 42 is connected to a terminal wire 48 leading to another terminal 50 of the power supply discussed.

The oscillator 42 is of a free-running, complimentary, astable multivibrator type and includes a pair of regenerative, complimentary transistors 52 and 54, respectively, located in back-to-back relationship. These transistors are conventional bipolar transistors. The collector of the transistor 52 is connected to the base of the transistor 54 by means of a wire 56. Similarly the base of the transistor 52 is connected by another wire 58 to the collector of the transistor 54 through a capacitor 60. The wire 44 is connected to the wire 58 between the capacitor 60 and the collector of the transistor 54.

In the circuit 10 a diode 62 is used in the oscillator 42 in the wire 36 leading to the emitter of the transistor 52 between the resistor 40 and the transistor 52. This diode 62 is considered beneficial in preventing the breakdown of the emitter-base junction in the transistor 52. However, the use of the diode 62 is not considered necessary to the successful operation of the circuit I0. Circuits corresponding to the circuit 10 have been operated successfully with the diode 62 omitted and with the resistor 40 being directly connected to the emitter of the transistor 52.

A wire 66 connected to the wire 36 between the resistors 38 and 40 is used to pass current to one end of the auxiliary winding 22 from the terminal 30. The other end of this auxiliary winding 22 is connected by a wire 68 to the points 16. A further wire 70 is used to connect the points 16 to the other wire 48 and the other terminal 50. If desired another condensor 72 may be connected by a wire 74 to the wires 68 and 70 around the points 16. This condensor 72 may be omitted in the circuit 10; when it is used it is considered to be effective in prolonging the effective life of the points 16 by tending to minimize or suppress the peak voltage appearing at the points 16.

In the circuit 10 the extremity of the winding 24 remote from the wire 26 is connected to the wire 68 by a further wire 76. This winding 24 is terminated in this manner essentially as a matter of convenience and if desired may be terminated in the circuit I0 in other conventional manners, as, for example, by the wire 76 being connected to the wire 48 instead of the wire 68. Also in the circuit 10 the spark plugs I4 are connected to the terminal 50 through a wire 78 leading to the wire 48.

When the circuit I0 is used for its intended purpose the switch 34 is of course closed. As a consequence of this, current will be directly supplied to the oscillator 42 through the wires 36 and 46 and current will also be supplied to this oscillator 42 through the transformer winding 20. As this occurs the winding 20 will act so as to in effect be a part of the oscillator 42. Both this winding 20 and the capacitor 60 will serve as timing elements which will determine the frequency and amplitude of the oscillation by this oscillator 42. If desired various other auxiliary means such as, for example, a

resistor (not shown) located between the base of transistor 52 and the wire 48 may be further used to control the operation of this oscillator 42. Such means are considered to be well known in the electronics field.

An important feature of the present invention lies in an additional element of control of the operation of the oscillator 42, achieved with the auxiliary winding 22. When the points 16 are closed current will flow through this auxiliary winding 22 and through the points 16, increasing the flux in the core of the transformer l8 and consequently lowering the inductance of the winding 20. This raises the frequency of the oscillator and reduces the amplitude of the oscillation and the amount of energy coupled to the secondary winding 24. Preferably when the points are closed the voltage amplitude is reduced to such an extent that a spark will not jump across the normal gap in a spark plug. As the points are opened the inductance of the winding 20 increases, oscillator frequency decreases, and maximum energy is coupled to the spark plugs to accomplish combustion.

As a consequence of this interaction the oscillator 42 is not shut off at any time as the circuit 10 is operated in conjunction with an engine. As a consequence of this each time the points 16 are opened the oscillator 42 output increases so as to supply energy to the transformer 18 in an amount and to an extent sufficient so that scintillation can be achieved at a spark plug 14. With this structure the transformer 18 acts as a means for coupling energy from the oscillator 42 so that the coupled energy may be used to cause scintillation at an individual spark plug 14 only as determined by the position of the distributor 12. While the transformer 18 performs this function it also serves as a part of the oscillator 42 in governing the operation of this oscillator.

As a consequence of the manner of operation described the circuit l0 if constructed as indicated will provide a high frequency series of repetitive current pulses at a spark plug 14 of a substantially uniform square wave character. It is considered that a substantially square wave shape is desirable in order to achieve efficient engine ignition or combustion and that in general the greater the frequency of these current pulses the more satisfactory the ignition achieved. Frequencies of at least 7 KH are presently preferred. The precise reasons for this are not understood, but are believed to relate to the energy supplied to a combustion chamber through a spark plug and to the combustion within such a chamber.

It is, however, clearly apparent that an ignition circuit such as the circuit 10 shown can be used to operate a conventional automotive engine to obtain waht what considered to be very desirable results. The achievement of such results over a long term period is considered to require the cooling of the components described in order to prevent thermal runaway in the oscillator 42 circuit. Such cooling can be easily accomplished in known manners, such as, for example, by the use of cooling fans.

As an example of this when a circuit corresponding to the circuit 10 was installed in a 1965 Chrysler automobile in which the internal combustion engine was of a high compression type and had been used to a significant extent tests on the emissions from the engine showed a presence of no readily detectable amounts of unburned hydrocarbons and a considerable lessening of carbon monoxide in the exhaust gas. Also a significant decrease in the gasoline consumption of the car was noted. Further, these results were achieved along with satisfactory engine performance while using various inexpensive grades of gasoline having a relatively low octane rating whereas before it was necessary to utilize so-called premium" or "high test" grades of gasoline having higher octane ratings in operating the car.

With this particular car the emissions of undesirable nitrogen oxides were not adequately controlled through the use ofa circuit corresponding to the circuit 10 alone. However, when the car was further modified so as to employ the recirculation of significant quantities of exhaust gases to the car's carburetor under controlled conditions as set forth in the afore mentioned application entitled Internal Combustion Engine Operation Using Exhaust Gases" the exhaust emissions showed a significant improvement as far as the undesirable nitrogen oxides content was concerned.

When this invention and the invention set forth in the other co-pending application were used together in an internal combustion engine the exhaust emissions were considered to be within reasonably acceptable ranges. Further, the engine performed satisfactorily utilizing commercial gasoline of a comparatively inexpensive character having a relatively low octane rating whereas before the engine required the use of a comparatively expensive type of gasoline having a relatively high octane rating. The vehicle referred to when the engine warmed up was as fully responsive as it was when operated prior to being modified so as to utilize the noted inventions. Further, very significant increases in gasoline mileage were observed.

We claim:

I. In an internal combustion engine ignition system having a power supply, a transformer having primary and secondary coils, a primary circuit including an oscillator connected across the terminals of the power supply and to the transformer primary coil, a secondary circuit including spark gap means connected in series with the secondary coil and said system also having switch means for controlling the operation of the oscillator, the improvement which comprises:

means for opening and closing said switch means in accordance with engine speed,

the transformer having a second primary coil which is connected in series with the switch means between the terminals of the power supply,

the oscillator means being connected to one terminal of the power supply through the first mentioned primary of the transformer and in addition being connected across the power supply,

the first mentioned primary coil and the second primary coil being positioned adjacent to one another so as to be inductively coupled,

the oscillator means being responsive to the coupling of the first mentioned and second primary coils so as to continuously operate at an amplitude which varies depending upon whether the switch means is open or closed and at a frequency which varies depending upon whether the switch means is open or closed.

2. An ignition system as claimed in claim I wherein:

said oscillator means is a free-running, complimentary astable, multivibrator oscillator.

3. An ignition system as claimed in claim I wherein:

said switch means comprise internal combustion engine ignition points which are opened and closed in accordance with engine speed.

4. An ignition system as claimed in claim I wherein:

said oscillator means is a free-running, complimentary, astable, multivibrator oscillator employing two regenerative, complimentary transistors connected in back-to-back relationship.

5. An ignition system as claimed in claim 1 wherein:

said secondary circuit includes a distributor and a plurality of spark plugs, said distributor being capable of sequentially connecting any of said spark plugs in said secondary circuit in accordance with engine speed,

said switch means comprises internal combustion ention amplitude each time said points are open. l =8 k 

1. In an internal combustion engine ignition system having a power supply, a transformer having primary and secondary coils, a primary circuit including an oscillator connected across the terminals of the power supply and to the transformer primary coil, a secondary circuit including spark gap means connected in series with the secondary coil and said system also having switch means for controlling the operation of the oscillator, the improvement which comprises: means for opening and closing said switch means in accordance with engine speed, the transformer having a second primary coil which is connected in series with the switch means between the terminals of the power supply, the oscillator means being connected to one terminal of the power supply through the first mentioned primary of the transformer and in addition being connected across the power supply, the first mentioned primary coil and the second primary coil being positioned adjacent to one another so as to be inductively coupled, the oscillator means being responsive to the coupling of the first mentioned and second primary coils so as to continuously operate at an amplitude which varies depending upon whether the switch means is open or closed and at a frequency which varies depending upon whether the switch means is open or closed.
 2. An ignition system as claimed in claim 1 wherein: said oscillator means is a free-running, complimentary astable, multivibrator oscillator.
 3. An ignition system as claimed in claim 1 wherein: said switch means comprise internal combustion engine ignition points which are opened and closed in accordance with engine speed.
 4. An ignition system as claimed in claim 1 wherein: said oscillator means is a free-running, complimentary, astable, multivibrator oscillator employing two regenerative, complimentary transistors connected in back-to-back relationship.
 5. An ignition system as claimed in claim 1 wherein: said secondary circuit includes a distributor and a plurality of spark plugs, said distributor being capable of sequentially connecting any of said spark plugs in said secondary circuit in accordance with engine speed, said switch means comprises internal combustion engine ignition points which are opened and closed in accordance with engine speed each time said distributor operates so as to include another of said spark plugs in said secondary circuit, said oscillator means is a free-running, complimentary, astable, multivibrator oscillator employing two regenerative, complimentary transistors connected in back-to-back relationship, said oscillator means increasing in its oscillation frequency and decreasing in oscillation amplitude each time said points are closed and decreasing in its oscillation frequency and increasing its oscillation amplitude each time said points are open. 